Automatic circuit breaker pan interlock

ABSTRACT

An apparatus includes a cell pan that supports a circuit breaker within a switchgear cell, and a lift pan that carries a circuit breaker outside of the switchgear cell. The lift pan has a track for a roller on the circuit breaker. The apparatus further includes an extension rail that interconnects the lift pan with the cell pan in an aligned position. With the lift pan in aligned position, the track on the lift pan can receive the roller upon horizontal draw-out movement of the circuit breaker from the cell pan. A latch on the extension rail has a blocking position in which it blocks the roller from rolling outward off the cell pan, and has a non-blocking position in which it does not block the roller from rolling outward off the cell pan. The latch automatically moves from the blocking position to the non-blocking position under the influence of the lift pan upon movement of the lift pan into the aligned position.

RELATED APPLICATIONS

This application is a continuation of U.S. patent applicant Ser. No.15/685,210, filed on Aug. 24, 2017, which claims priority of provisionalU.S. Patent Application 62/518,690, filed Jun. 13, 2017, which isincorporated by reference.

TECHNICAL FIELD

This technology includes a cell pan for supporting a horizontal draw-outcircuit breaker in a switchgear cell, and further includes a mechanismfor blocking draw-out movement of the circuit breaker from the cell pan.

BACKGROUND

A horizontal draw-out circuit breaker is operatively installed within aswitchgear cell. The switchgear cell contains a cell pan with rails. Thecircuit breaker has rollers for moving into and out of the switchgearcell along the rails. A lift pan is provided to carry the circuitbreaker on a lifting device that can be rolled across a floor totransport the circuit breaker to and from the switchgear cell. When thelift pan is moved into alignment with the cell pan, the circuit breakercan be withdrawn from the switchgear cell by rolling the circuit breakeroutward from the cell pan onto the lift pan. The cell pan is equippedwith latches that normally retain the circuit breaker within theswitchgear cell by blocking the rollers from rolling off the cell pan.When the latches on the cell pan are disengaged, the circuit breaker isfree to roll outward off the cell pan.

SUMMARY

An apparatus is configured for use with a circuit breaker, a cell panthat supports the circuit breaker in a switchgear cell, and rollers thatsupport the circuit breaker on the cell pan for horizontal draw-outmovement from the cell pan. The apparatus includes a lift pan thatcarries the circuit breaker outside of the switchgear cell. The lift panhas a track for a roller on the circuit breaker. The apparatus furtherincludes an extension rail that interconnects the lift pan with the cellpan in an aligned position. With the lift pan in aligned position, thetrack on the lift pan can receive the roller upon horizontal draw-outmovement of the circuit breaker from the cell pan. A latch is supportedon the extension rail for movement relative to the extension rail. Thelatch has a blocking position in which it blocks the roller from rollingoutward off the cell pan, and has a non-blocking position in which itdoes not block the roller from rolling outward off the cell pan. Thelatch automatically moves from the blocking position to the non-blockingposition under the influence of the lift pan upon movement of the liftpan into the aligned position.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a circuit breaker with other parts andassemblies for providing and controlling horizontal draw-out movement ofthe circuit breaker.

FIG. 2 is an enlarged perspective view of parts shown in FIG. 1.

FIG. 3 is a view similar to FIG. 2, showing fasteners interconnectingthe parts.

FIG. 4 is top view of the parts as shown in FIG. 3.

FIG. 5 is an opposite side view of the parts shown in FIG. 2.

FIG. 6 is an enlarged side view of other another part shown in FIG. 1.

FIG. 7 is a perspective of the part shown in FIG. 6.

DETAILED DESCRIPTION

The structures illustrated in the drawings include examples of theelements recited in the claims. The illustrated structures thus includeexamples of how a person of ordinary skill in the art can make and usethe claimed invention. These examples are described to meet theenablement and best mode requirements of the patent statute withoutimposing limitations that are not recited in the claims. One or more ofthe elements of one embodiment may be used in combination with, or as asubstitute for, one or more elements of another as needed for anyparticular implementation of the invention.

As shown in FIG. 1, an apparatus includes a circuit breaker 10 and acell pan 12. The cell pan 12 is configured to support the circuitbreaker 10 in a position operatively installed within a switchgear cell(not shown), as known in the art. Rollers 14 support the circuit breaker10 on the cell pan 12 for horizontal draw-out movement from the cell pan12 in a direction from left to right as viewed in FIG. 1. The apparatusfurther includes a lift pan 18 that is configured to carry the circuitbreaker 10 on a lifting device (not shown) which, as known in the art,can be rolled across a floor to transport the circuit breaker 10 to andfrom the switchgear cell.

The cell pan 12 has a pair of opposite side rails 20. Each side rail 20has an upper edge 22 defining a track for the rollers 14 at thecorresponding side of the circuit breaker 10. A frame 24 at each siderail 20 defines a slot 25. A hub 26 projects from the side rail 20 at alocation slightly inward of the frame 24. A stop member 28 projects fromthe side rail 20 at a location spaced inward from the hub 26.Additionally, a latch 30 is mounted on the side rail 20 for rotation onthe side rail 20. The latch 30 normally takes a raised position in whichan inner corner portion 32 of the latch 30 projects upward into the pathof movement of the rollers 14 along the upper edge 22. In this mannerthe latch 30 normally blocks the circuit breaker 10 from rolling outwardoff the cell pan 12.

Also shown in FIG. 1 are a pair of extension rail assemblies 50. Theextension rail assemblies 50 are configured to interconnect the lift pan18 with cell pan 12 in an aligned position in which the circuit breaker10 can roll outward from the cell pan 12 onto the lift pan 18. Theextension rail assemblies 50 are further configured to block the circuitbreaker 10 from rolling outward off the cell pan 12 when the lift pan 18is not interconnected in the aligned position. As shown in FIG. 1, theextension rail assemblies 50 are oriented oppositely relative to eachother at opposite sides of the apparatus, but are otherwise alike. Eachextension rail assembly 50 thus includes an extension rail 60, a latch62, and a lock plate 64.

As shown in greater detail in FIGS. 2-5, each extension rail 60 has aninner end 70, a lower notch 72, and an upper shoulder 74 between thelower notch 72 and the inner end 70. In this configuration, theextension rails 60 can be releasably installed at the side rails 20 onthe cell pan 12, as shown in FIG. 1. Specifically, an extension rail is60 inserted through the slot 25 at the frame 24 on the correspondingside rail 20. The lower notch 72 is received on the hub 24. Theextension rail 60 can then be rotated about the hub 24 to move the uppershoulder 74 against the stop member 28. This causes the inner end 70 ofthe extension rail 60 to move upward against the latch 30, and therebyto rotate the latch 30 from the raised position to a lowered position,as shown in FIG. 1.

When the latch 30 is in the lowered position of FIG. 1, it no longerblocks the rollers 14 on the upper edge 22 of the side rail 20. However,as noted above, the extension rail assemblies 50 block the circuitbreaker 10 from rolling outward off the cell pan 12 when the lift pan 18is not interlocked in the aligned position. This is accomplished by thelatches 62 and the lock plates 64.

Referring again to FIGS. 2-5, each lock plate 64 is fixed to therespective extension rail 60 by fasteners 80. An inner edge 82 of thelock plate 64 defines a J-hook slot 83 reaching inward from an outer end84 of the lock plate 64. Each latch 62 is supported on the respectivelock plate 64 by a hub 86 at which the latch 62 is movable relative tothe lock plate 64 pivotally about an axis 87. A stop member 88 projectsfrom the latch 62 through an arcuate slot 89 in the lock plate 64 todefine a range of pivotal movement along the length of the slot 89.

When the extension rail assemblies 50 are installed on the cell pan 12as described above with reference to FIG. 1, the latches 62 on theextension rail assemblies 50 normally take positions in which an innercorner portion 90 of each latch 62 projects upward beyond the upper edge22 of the adjacent side rail 20 on the cell pan 12. The latches 62 thenblock the rollers 14 from rolling outward off the cell pan 12. In theillustrated example, the hubs 86 are located relative to the latches 62such that each latch 62 is normally retained in the blocking position bythe force of gravity urging the latch 62 pivotally about the respectiveaxis 87 toward and into the blocking position.

The lift pan 18 has a pair of opposite side rails 100. Each side rail100 has an upper edge 102 defining a track for the rollers 14 at thecorresponding side of the circuit breaker 10. Each side rail 100 alsohas a laterally projecting rail guide 104. Each rail guide 104 has aweld boss 106 (FIGS. 6 and 7) at which the rail guide 104 is welded tothe respective side rail 100.

As noted above, the lift pan 18 is carried on a lifting device, and ismovable from the position of FIG. 1 into engagement with the extensionrail assemblies 50. As the lift pan 18 approaches the extension railassemblies 50, central portions 108 of the rail guides 104 are receivedin the J-hook slots 83 in the lock plates 64. Conical surfaces 110 atopposite ends of the central portions 108 can slide against the inneredge surfaces 82 of the lock plates 64 within the J-hook slots 83 asneeded to guide the side rails 100 on the lift pan 18 into alignmentwith the side rails 20 on the cell pan 12. The lift pan 18 is therebyaligned with the cell pan 12 so as to receive the rollers 14 uponhorizontal draw-out movement of the circuit breaker 10 outward from thecell pan 12. The lift pan 18 becomes releasably interconnected with theextension rail assemblies 50 in the aligned position when the centralportion 108 of each rail guide 104 reaches the bottom of thecorresponding J-hook slot 83.

In addition to establishing an interlock between the lift pan 18 and thelock plates 64, the rail guides 104 on the lift pan 18 push against thelatches 62 to move the latches 62 pivotally about the axes 87. As thecentral portions 108 of the rail guides 104 move through the J-hookslots 83, enlarged end portions 118 of the rail guides 104 contact andadvance inwardly against outer edges 120 of the latches 62. This pivotsthe latches 62 so as to move the corner portions 90 downward topositions in which they do not block the rollers 14 from rolling outwardoff the side rails 20. The circuit breaker 10 is thus released forremoval from the cell pan 12 automatically by the action of interlockingthe lift pan 18 with the extension rail assemblies 50. When the lift pan18 is subsequently disconnected by removing the rail guides 104 from theJ-hook slots 83, the latches 62 return pivotally back into their lockingpositions under the force of gravity.

This written description sets for the best mode of carrying out theinvention, and describes the invention so as to enable a person ofordinary skill in the art to make and use the invention, by presentingexamples of the elements recited in the claims. The detaileddescriptions of those elements do not impose limitations that are notrecited in the claims, either literally or under the doctrine ofequivalents.

The invention claimed is:
 1. An apparatus for use with a circuit breakerand a cell pan configured to support the circuit breaker in a switchgearcell, the cell pan having a cell pan track for horizontal draw-outmovement of the circuit breaker, the apparatus comprising: a lift panconfigured to carry the circuit breaker outside of the switchgear cell,the lift pan having a lift pan track for horizontal draw-out movement ofthe circuit breaker; an extension rail configured to interconnect thelift pan with the cell pan in an aligned position for the lift pan trackto receive the circuit breaker from the cell pan track; a latchsupported on the extension rail for movement relative to the extensionrail between a blocking position where the latch blocks horizontaldraw-out movement of the circuit breaker on the cell pan track and anon-blocking position where the latch does not block horizontal draw-outmovement of the circuit breaker on the cell pan track, and the latch isheld in the blocking position by the lift pan when the lift pan is inthe aligned position; and interconnecting means for releasablyinterconnecting the lift pan with the extension rail in response tomovement of the lift pan into the aligned position.
 2. An apparatus asdefined in claim 1 wherein the latch is supported on the extension railto move from the non-blocking position to the blocking position underthe force of gravity.
 3. An apparatus as defined in claim 1 wherein thelatch is supported on the extension rail to normally remain in theblocking position under the force of gravity.
 4. An apparatus as definedin claim 1 wherein the latch is supported on the extension rail formovement between the blocking position and the non-blocking positionpivotally about an axis.
 5. An apparatus as defined in claim 1 whereinthe latch is supported on the extension rail to be moved into theblocking position by advancing contact of the lift pan.
 6. An apparatusas defined in claim 1 wherein the lift pan has a guide member, and theextension rail has a slot configured to receive the guide member uponmovement of the lift pan toward the aligned position.
 7. An apparatus asdefined in claim 6 wherein the guide member is movable against the latchto move the latch into the blocking position upon movement of the guidemember in the slot.
 8. An apparatus as defined in claim 6 wherein theinterconnecting means includes the guide member on the lift pan and theslot in the extension rail, the slot is a J-hook slot having a bottom,and the interconnecting means releasably interconnects the lift pan withthe extension rail upon movement of the guide member to the bottom ofthe J-hook slot.
 9. An apparatus for use with a circuit breaker and acell pan configured to support the circuit breaker in a switchgear cell,the cell pan having a cell pan track for horizontal draw-out movement ofthe circuit breaker, the apparatus comprising: a lift pan configured tocarry the circuit breaker outside of the switchgear cell, the lift panhaving a lift pan track for horizontal draw-out movement of the circuitbreaker; an extension rail configured to interconnect the lift pan withthe cell pan in an aligned position for the lift pan track to receivethe circuit breaker from the cell pan track; and a latch supported onthe extension rail for movement relative to the extension rail between ablocking position where the latch blocks horizontal draw-out movement ofthe circuit breaker on the cell pan track and a non-blocking position inwhere the latch does not block horizontal draw-out movement of thecircuit breaker on the cell pan track, and the latch is held in thenon-blocking position by the lift pan in the aligned position; whereinthe latch is supported on the extension rail to return from thenon-blocking position to the blocking position under the force ofgravity.
 10. An apparatus as defined in claim 9 wherein the latch issupported on the extension rail to normally remain in the blockingposition under the force of gravity.
 11. An apparatus as defined inclaim 9 wherein the latch is supported on the extension rail formovement between the blocking position and the non-blocking positionpivotally about an axis.
 12. An apparatus as defined in claim 9 whereinthe lift pan has a guide member, and the extension rail has a slotconfigured to receive the guide member.
 13. An apparatus as defined inclaim 12 wherein the guide member is movable against the latch to movethe latch into the blocking position upon movement of the guide memberin the slot.
 14. An apparatus as defined in claim 12 wherein the slot isa J-hook slot.
 15. An apparatus for use with a circuit breaker,comprising: a cell pan configured to support the circuit breaker in aswitchgear cell, the cell pan having a cell pan track for horizontaldraw-out movement of the circuit breaker; a first latch supported on thecell pan for movement between a blocking position where the first latchblocks horizontal draw-out movement of the circuit breaker on the cellpan track and a non-blocking position where the first latch does notblock horizontal draw-out movement of the circuit breaker on the cellpan track; a lift pan configured to carry the circuit breaker outside ofthe switchgear cell, the lift pan having a lift pan track for horizontaldraw-out movement of the circuit breaker; an extension rail configuredto interconnect the lift pan with the cell pan in an aligned positionfor the lift pan track to receive the circuit breaker from the cell pantrack, wherein the extension rail is configured for attachment to thecell pan track in an installed position where the extension railsupports the first latch in the non-blocking position; and a secondlatch supported on the extension rail for movement between a blockingposition where the second latch blocks horizontal draw-out movement ofthe circuit breaker from the cell pan track onto the lift pan track anda non-blocking position where the latch does not block horizontaldraw-out movement of the circuit breaker from the cell pan track ontothe lift pan track, and the second latch is held in the blockingposition by the lift pan when the lift pan is in the aligned position.16. An apparatus as defined in claim 15 wherein the second latch issupported on the extension rail to move from the non-blocking positionto the blocking position under the force of gravity.
 17. An apparatus asdefined in claim 15 wherein the second latch is supported on theextension rail to normally remain the blocking position under the forceof gravity.
 18. An apparatus as defined in claim 15 further comprisinginterconnecting means for releasably interconnecting the lift pan withthe extension rail in response to movement of the lift pan into thealigned position.
 19. An apparatus as defined in claim 15 wherein thelift pan has a guide member, the extension rail has a slot configured toreceive the guide member upon movement of the lift pan toward thealigned position, and the guide member is movable against the latch tomove the latch into the blocking position upon movement of the guidemember in the slot.
 20. An apparatus as defined in claim 19 wherein theinterconnecting means includes the guide member on the lift pan and theslot in the extension rail, the slot is a J-hook slot having a bottom,and the interconnecting means releasably interconnects the lift pan withthe extension rail upon movement of the guide member to the bottom ofthe J-hook slot.